The invention relates to a device for printing on paper tape and for cutting the tape into printed tickets, more precisely it relates to a device for printers of the type comprising a thermal print head carried resiliently by a frame, and a tape-drive roller or xe2x80x9ccapstanxe2x80x9d carried by a cover and parallel to a hinge axis, with the print head co-operating in operation with the roller by bearing against a generator line thereof.
Numerous variant embodiments of ticket printing and dispensing devices of the above type are already in existence and they can be classified as closed devices and as open device.
In closed devices, there is generally a moving cap which enables a roll of tape to be inserted into a paper compartment and means for threading the leading end of the tape between the head and the capstan and between two blades of the cutter device.
In open devices, there is a frame and a cover, one carrying the print head and the other the capstan, so the capstan and the print head can be moved apart from each other in order to place the leader of the tape between them without it being necessary to have means for inserting and threading said end. In general, such devices have a cutter device downstream from the print unit, which cutter can be static (with cutting being performed by pulling on the ticket) or it can be motor driven. When motor driven, the motor-driven cutter device can be of the opening kind having one blade carried by the cover and another blade carried by the frame (in general this is the motor-driven blade), or else it can be of the non-opening type.
Static cutter devices are subject to random operation because of intervention by the user who exerts traction more or less correctly for detaching the ticket.
Opening motor-driven cutter devices are complex mechanically and subject to frequent breakdowns because of the play which exists between the two blades specifically because they can be separated.
Finally, non-opening cutter devices generally include paper guide means upstream from the cutter blades which form a tunnel making it awkward to engage the leader end of the tape each time the roll is changed.
The present invention provides a remedy to the drawbacks of all known devices by using a printer structure which opens and a cutter device structure which does not open but which has simplified access.
To this end, the invention provides a device for printing a paper tape and for cutting the tape into printed tickets, the device comprising a frame with a cover hinged to the frame, a printer comprising a thermal print head carried resiliently by the frame and cooperating in operation by bearing against a generator line of a tape drive roller mounted to rotate on the cover, cutter means downstream from the print head in the tape drive direction comprising a fixed blade whose cutting edge extends parallel to the axis of the drive roller and a knife that is movable along the edge of the fixed blade, and guide means for guiding the tape between the printer and the cutter means, wherein the guide means are formed by two walls substantially parallel to the axis of the roller, one of the walls being carried by the cover downstream from the roller and the other wall being carried by the frame upstream from the cutting edge of the fixed blade, the walls imposing an S-bend on the portion of tape that extends between the printer and the cutting edge of the fixed blade.
This S-bend confers stiffness to the portion of tape that facilitates the cutting operation since the tape is then better at withstanding the lateral drive forces to which it is subjected while the knife passes along the edge of the fixed blade.
In preferred manner, the cutting edge is constituted by a downstream edge of the fixed wall.
In this way, the functions of guidance and of cutting are performed by the same element.
The moving knife is then advantageously carried by a carriage that moves parallel to the edge of the fixed blade, and the fixed blade is longer than the width of the paper tape so that the portion thereof projecting beyond the tape forms a parking zone for the moving knife.
Thus, clearing a passage for the tape leader while it is being put into place is achieved merely by placing the moving knife in the parking zone.
The moving carriage is advantageously actuated by a wormscrew extending parallel to the edge of the fixed blade.
The carriage is thus easily displaced using a motor to drive the wormscrew.